In a global ecological sense, it is worse to eat fish than pork, we are sucking the seas dry, we have known it for decades, and invented new methods to do it more efficiently.
With land animals you can see the conditions and the effect of over production, with fish you don't, and we keep at it.
Grown fish is less bad, but still contribute to pollution of the seas.
Trawling should be banned globally for a minimum of 50 years.
We have also invented ways to do it more sustainably, and even have handy wallet sized Sustainable Seafood Lists for each region of the US to make sure you make sustainable choices when eating at restaurants or purchasing at the market Seafood Watch Guides
@Alue42 we used to have these in New Zealand. It was a card you could keep in your wallet, listed all the common eating fish from best to worst, with sustainable ones coded green at the top and endangered ones in red.
But it was depressing over the years with each new edition to slowly see all those green fish turning orange and then red as each species became depleted.
I just tried looking for you, and the most up to date I could find was for 2017. That's disappointing, but slightly out of date is better than nothing.
By 2017 it had already happened - almost all the NZ fish had gone from the green zone and they'd started putting farmed shellfish and stuff caught in international waters at the top of the list to make up for it.
I think those of us who care about our local marine environment seldom eat actual fish now. We don't really need a guide any more.